This invention relates to a processing container for foodstuffs.
From DE-3117773 A1 there is already known an electrical household appliance with a cup-type attachment in which a cutting mechanism adapted to be driven by a drive motor is arranged. The cutting mechanism is equipped with a slow-down brake for bringing the drive motor to a quick standstill. In this arrangement the brake is positioned between a mountable lid and a motor base. When the lid is interlocked with the motor base, an associated latching device is moved downward and the friction lining provided between the lid and the base is removed from a driving disk so that the brake is no longer able to act between the processing tool and the appliance. Such a brake can only be used, however, on a household appliance with a suitable constructional design.
EP-0221392 B1 discloses a cornminuting appliance for comminuting, for example, parsley, onions etc., which includes a lid and a container closable by the lid. The lid has a first and a second coupling member as a coupling device, which are interconnected by a gear arrangement. The second coupling member situated in the container is rotatably connectable to a blade rotatable in the container. To drive the blade the first coupling member is made to engage with the processing tool of a kitchen machine, for example with the blade of an immersion blender, so that after the immersion blender is switched on the rotating processing tool sets the first coupling member in rotation, and the blade in the container is likewise caused to rotate via the gearing and the second coupling member. When the immersion blender is removed from the first coupling member, thus interrupting the drive train to the blade provided in the container of the comminuting appliance, said blade will continue to run on for some time on account of its inertia, particularly when there is no food in the container. This may result in injuries to an operator""s hand if he or she raises the lid from the container and reaches inside the container to remove the blade from the container when the blade is still rotating.
DE-A-2250177 discloses a kitchen appliance in which a brake acting on the processing tool is provided in the transmission path from the drive motor to the processing tool. In this arrangement the brake is controlled by a pressure rod which passes through the center of the drive mechanism and the blade and is itself controlled by the lid of the appliance. The processing tool itself is rotatably or immovably mounted in the bottom of the kitchen appliance.
Finally, EP 0 529 287 B1 discloses a comminuting device for an electrical kitchen appliance. In the device a tool shaft is connectable to a drive shaft via a coupling arrangement. In this state of the art a brake controllable by a spring is provided in the tool shaft between the coupling arrangement and the processing tool. The spring displaces the tool shaft upon disengagement in axial direction until brake elements fitted to the inner circumference of the hollow tool shaft cooperate with corresponding brake elements at the lower shaft bearing, causing the tool shaft to be braked.
It is an object of the present invention to provide an improved processing container for foodstuffs in which the risk of injury to users from rotating tools is considerably reduced. At the same time the processing container should afford simplicity and economy of manufacture.
In some embodiments, the invention considerably reduces the risk of injury for users from rotating tools because the tool shaft is automatically braked upon removal of the container lid. At the same time the processing container affords simplicity and economy of manufacture using, for example, a plastics material. The rotating tool shaft is simply braked in that, after the container lid is raised, said shaft tilts about the lower bearing, its lower end running against the lower bearing. Through the tilting movement the center axis of the tool shaft intersects the perpendicular at an acute angle. This creates in astonishingly simple manner a brake mechanism whose effectiveness is based solely on the fact that the center of gravity of the tool shaft lies above the ball head of the bearing journal and an unstable state of equilibrium develops when the upper bearing is removed. After the tool shaft tilts it rests on the ball head on the one hand and on a point of contact between the tool shaft and the bearing bushing on the other hand. At this point of contact the residual rotation of the tool shaft attributable to inertia is braked by mechanical friction.
Unlike some embodiments of the art, no elaborate braking mechanism with moveable parts is formed within the tool shaft. Dirt accumulation in hard-to-reach recesses and accordingly unhygienic conditions of the processing container are thus avoided. The tool shaft is completely enclosed and water-tight.
Such a processing container can be used, for example, on generally known kitchen appliances. However, it can also be used, accordingly modified in construction, on stand blenders and cornminuting appliances.
A particularly advantageous embodiment provides for bearing the lower end of the tool shaft rotatably and tiltably in a simple manner. The bearing journal and the ball head are made of a suitable solid material such as brass or steel. The ball socket is made of a plastics material suitable for plain bearings.
The bearing journal bushing may be joined by adhesive bonding to the container bottom, for example, provided a suitable material is selected. Projections of the bearing journal bushing may be provided to enhance the braking effect.
In some cases the shaft upper bearing arrangement performs a multiple function, namely a transmission function for the drive torque on the one hand and a bearing function on the other hand. The coupling can be accomplished by a simple positive coupling, such as with spur gearing. The bearing arrangement of the coupling mount can be constructed as a plain bearing or a rolling bearing.
The coupling mount may be constructed, for example, in the form of a plastic injection molded part coupled to the drive shaft.
By constructing the tool shaft as a hollow shaft made of a plastics material, the braking operation may be additionally accelerated because the moment of inertia of such a shaft is very small and therefore only a low residual torque exists after decoupling.
Some embodiments play a particularly important role because of the particularly high risk of injury existing with the extremely sharp blades customary in household machines.
Further embodiments and advantages of the present invention will be described in the following with reference to the accompanying drawings.